This invention relates to a mechanism for braking a weft yarn in a weaving machine. More particularly, this invention relates to a a mechanism employing a flexible brake band for braking a weft yarn in a weaving machine.
Heretofore, various types of mechanisms have been employed for the braking of a weft yarn in a weaving machine. For example, as described in Swiss Pat. No. 497,576, one known mechanism employs a flexible brake band having ends which are secured to carrier means in the form of pivotably mounted arms as well as a brake member for pressing a weft yarn against the brake band. In addition, a tension spring is used to return the pivotably mounted arms of the carrier means. However, a disadvantage of this mechanism is that the pivotable mounting of the carrier arms is complicated and requires a considerable amount of space. Further, relatively large masses have to be moved. Another disadvantage is that the pivotable parts and the tension spring are susceptible to soiling by flying dust. This, in turn, impairs the operation of the mechanism.
Accordingly, it is an object of the invention to provide a braking mechanism of simple and compact construction which is reliable in operation.
It is another object of the invention to improve the reliability of a weft yarn braking mechanism employing a flexible brake band.
Briefly, the invention provides a mechanism for braking a weft yarn in a weaving machine which employs a flexible brake band, means for guiding a weft yarn over the brake band and at least one brake member for pressing the weft yarn against the brake band. In accordance with the invention, the mechanism has at least one linearly movable carrier which mounts the brake band thereon and a return means for displacing the carrier during pressing of the weft yarn against the brake band. The mechanism is relatively compact and is of simple construction with relatively small moving masses. Further, the accumulation of dust does not have any appreciable effect on the function of the yarn brake.
In order to provide a particularly effective protection of the mounting against dust, the carrier can be telescopically mounted in a sleeve.
The return means may be in the form of a compression spring which is also mounted in the sleeve. This provides practically complete encapsulation of the return means.
In addition, the compression spring may engage an adjusting screw which is mounted in the carrier and which engages the spring. This screw may be used to make very simple adjustments in the compression force of the spring.